1. Field of Invention
The invention relates generally to a wireless lock and key system and more particularly to controlling and managing an electronic lock, key and control device, and to creating easily distributable temporary keys to said locks.
2. Description of the Prior Art
Current locks are all based on the principle of a shared secret between the lock and the key. There are four main lock types, and each has its problems:                1) Mechanical locks, where the secret is the way the key is formed.                    The user has to carry a separate key for each lock he can access.             The keys have to be dug out of handbag or pocket every time a door is opened.            Distribution of keys is cumbersome and has to be done by hand.            Creating keys requires special equipment.            Invalidating keys is hard.            The use of keys cannot easily be limited (e.g. to office hours).                        2) Electronic locks with (possibly wireless) keys, where the secret is an access code stored in both lock and key.                    While a key may have space for several codes, this is uncommon and the number of codes is limited. Thus, the user still has to carry many keys, especially as the systems are incompatible with each other. Note that if the same code is used in all locks, then the owner of any lock is able to create a key for opening all the other locks. Thus, you would have to trust the owners of all locks that you use.            Distribution of keys is cumbersome and has to be done by hand.            Creating new keys usually requires special equipment, and even if a key can store several codes, access to the lock is required. While access to the lock is not necessary if a single, known code for the lock is always used, this would also mean that all the created keys share the same code and cannot be separately controlled. For instance, it would not be possible to revoke just a single key.                        3) Keyless mechanical or electronic locks, where the user has to remember the code and enter it whenever access is needed.                    While the user does not have to carry keys, he has to remember all his codes, which is actually worse for many people.            Creating new keys (codes) requires access to the lock.            While codes can be distributed electronically, they can be used by anyone, making use of secure channels necessary.            The code can be learned by secretly observing the user as he enters the code.                        4) Keyless electronic locks, where the user's fingerprint, retinal scan or other similar feature is used for identification.                    The required scanning devices are expensive.            Creating new “keys” requires access to the lock.                        In theory, if your information is stored on a lock, the owner of that lock can use that information to e.g. create a replica of your finger for opening all locks you have access to.        
U.S. Pat. No. 6,098,056 shows a method for controlling access to data through the Internet. A server is coupled to a storage device for storing the data which is encrypted using a random generated key. This is further encrypted with the server's public key. A trusted information handler is validated by the server. After the handler has been authenticated, the server key decrypts the data with its private key and re-encrypts the data with the handler's public key.
U.S. Pat. No. 6,289,455 shows a cryptographic method to regulate access to data. Rights keys which allow access to the data are added to a cryptographic unit by transforming data received from a control processor and storing the result. The unit then produces content decrypting keys by storing rights keys to transform other data received from a processor. Because the processor design has the ability to directly access the protected memory, security can remain effective even if the processor is compromised.
U.S. Pat. No. 5,673,316 shows a method to control access to data using cryptographic envelopes. An envelope is an aggregation of information parts, where each of the parts to be protected are encrypted with a corresponding part encryption key. Each part encryption key is also encrypted with a public key.
U.S. Pat. No. 4,914,698 shows method for issuing blind digital signatures which are untraceable.
International PCT published application 01/22760 shows a system for setting up a wireless transmission connection transmit identification messages.
While the prior art shows a number of different types of key and lock arrangements, they are all subject to a number of shortcomings by requiring the carrying of a number of keys or knowing various codes.